Add field_verbose_name template tags

Ref. #15
Make API_SRID a constant
Make date_update field optional

Don't cache if this field is missing
Add a default layer if there isn't any
Add pip requirements file for developer tools
Update doc after having set up a fresh project
Specify django-appypod version
Update setup documentation
Merge branch 'fresh-project-fixes' into develop

Conflicts:
	setup.py
PEP8ization